PURPOSE: To provide an oscillating measuring device that is constituted so as to smoothly perform each operation of a pickup and a vibro-exciter where a magnet and a coil are relative-displaceably combined together.

CONSTITUTION: A mass flow meter 1 makes a fluid pass through two sensor tubes 7 and 8 being vibrated by a vibro-exciter unit 19, and detects Coriolis effect in a size conformed to a flow rate, namely, a time difference by means of pickup units 20 and 21. This vibro-exciter unit 19 and the pickup units 20 and 21 are all supported by respective support plates 23 and 24 locked to the sensor tubes 7 and 8. A guide mechanism guiding a relative displacement direction between a coil 19a and a magnet 19b is installed in each vibro-exciter of the unit 19. A magnet support member supporting the magnet 19b is borne by a bearing housed in a coil support member supporting the coil 19a free of slide motion in the axial direction.